The invention relates to a clamping device for clamping the form tools of an injection molding machine to form supports, comprising at least two and preferably four clamping bolts on the rear side of each form tool, which are perpendicular to the form parting plane and protrude into holes in the form support, and locking means for the form tools.
In general, when fastening form tools to form supports, the holding means for the respective tool part are arranged in the form space between the supports. As a result damage caused by the form easily occured and, further, access to the form parts between the tension rods was difficult. Another problem was caused by the fact that without excessive expenses they could hardly be made sufficiently stable to absorb high tool opening forces.
The DE-OS No. 27 24 020 suggests to provide a clamping device for clamping the form parts of an injection molding machine to the form supports in which each form part has guide bolts at its rear side which are perpendicularly aligned to the form parting plane, protrude through bores in the form support and project beyond the rear side of the form support. On the rear side of the tool support transverse slide means are arranged which engage in lateral openings in the guide bolts and press the form part against the form support by means of a wedge surface.
It was the object of this document to arrange the clamping means, i.e. the transverse slide means, no longer in the form space between the supports and to protect them, thus, from being damaged. This construction has proved unsuitable for use in practice because the length of the guide bolts, which must be longer than the width of the form supports, would require excessive opening distances in order to be able at all to exchange the form tools. Another disadvantage would result from the use of the guide bolts as fastening means. This would require that the guide bolts and the corresponding bores in the tool supports be extremely precise, so that the form tools are properly centered--a problem which grows naturally the harder the more guide bolts are necessary for fastening a form tool to the form support.